<s>
The	O
Time	B-Device
Independent	I-Device
Escape	I-Device
Sequence	I-Device
,	O
or	O
TIES	O
,	O
is	O
a	O
modem	B-Application
protocol	O
standard	O
invented	O
to	O
avoid	O
a	O
patent	O
held	O
by	O
Hayes	O
Microcomputer	O
Products	O
.	O
</s>
<s>
TIES	O
is	O
an	O
escape	O
sequence	O
that	O
switches	O
the	O
modem	B-Application
from	O
"	O
data	O
mode	O
"	O
to	O
"	O
command	O
mode	O
"	O
,	O
allowing	O
instructions	O
to	O
be	O
sent	O
to	O
the	O
modem	B-Application
to	O
control	O
it	O
while	O
still	O
connected	O
to	O
the	O
remote	O
modem	B-Application
.	O
</s>
<s>
When	O
inventing	O
the	O
first	O
Smartmodem	O
,	O
Dale	O
Heatherington	O
was	O
faced	O
with	O
the	O
problem	O
of	O
distinguishing	O
commands	O
from	O
data	O
given	O
that	O
there	O
were	O
only	O
two	O
serial	B-Protocol
pins	I-Protocol
available	O
for	O
use	O
in	O
the	O
RS-232C	O
port	O
.	O
</s>
<s>
Of	O
course	O
,	O
files	O
being	O
sent	O
over	O
the	O
modem	B-Application
could	O
contain	O
the	O
string	O
+++	O
.	O
</s>
<s>
If	O
the	O
modem	B-Application
simply	O
looked	O
for	O
the	O
string	O
to	O
arrive	O
in	O
the	O
data	O
stream	O
also	O
carrying	O
this	O
text	O
,	O
it	O
would	O
switch	O
to	O
command	O
mode	O
at	O
inappropriate	O
times	O
and	O
stop	O
data	O
transfer	O
with	O
the	O
remote	O
modem	B-Application
.	O
</s>
<s>
A	O
file	O
containing	O
the	O
string	O
being	O
sent	O
would	O
not	O
contain	O
the	O
pauses	O
,	O
so	O
the	O
modem	B-Application
would	O
treat	O
it	O
as	O
data	O
to	O
be	O
sent	O
,	O
and	O
stay	O
in	O
data	O
mode	O
.	O
</s>
<s>
A	O
user	O
typing	O
in	O
the	O
string	O
deliberately	O
would	O
naturally	O
pause	O
after	O
sending	O
it	O
to	O
wait	O
for	O
the	O
modem	B-Application
's	O
response	O
,	O
inserting	O
the	O
pause	O
without	O
even	O
being	O
aware	O
of	O
it	O
.	O
</s>
<s>
Eaton	O
's	O
company	O
,	O
Business	O
Computers	O
Corp.	O
,	O
or	O
Bizcomp	O
for	O
short	O
,	O
introduced	O
modems	B-Application
using	O
this	O
system	O
in	O
1980	O
,	O
before	O
the	O
Smartmodem	O
.	O
</s>
<s>
In	O
1984	O
,	O
USR	O
sued	O
Bizcomp	O
in	O
an	O
effort	O
to	O
break	O
the	O
patent	O
on	O
the	O
basis	O
of	O
obviousness	O
and	O
prior-art	O
,	O
and	O
violation	O
of	O
the	O
Sherman	O
Antitrust	O
Act	O
in	O
their	O
efforts	O
to	O
monopolize	O
the	O
modem	B-Application
market	O
.	O
</s>
<s>
They	O
received	O
patent	O
#4	O
,	O
549,302	O
in	O
October	O
1985	O
,	O
Modem	B-Application
With	O
Improved	O
Escape	O
Sequence	O
With	O
Guard	O
Time	O
Mechanism	O
,	O
commonly	O
known	O
as	O
the	O
"	O
Hayes	O
'	O
302	O
"	O
or	O
the	O
"	O
Heatherington	O
'	O
302	O
"	O
.	O
</s>
<s>
In	O
October	O
1986	O
,	O
Hayes	O
began	O
sending	O
notices	O
for	O
license	O
fees	O
of	O
2%	O
per	O
modem	B-Application
to	O
any	O
vendor	O
using	O
the	O
guard	O
time	O
concept	O
.	O
</s>
<s>
This	O
included	O
any	O
modem	B-Application
already	O
manufactured	O
,	O
and	O
Hayes	O
sent	O
bills	O
for	O
millions	O
of	O
dollars	O
to	O
a	O
number	O
of	O
major	O
manufacturers	O
.	O
</s>
<s>
For	O
makers	O
of	O
low-cost	O
modems	B-Application
,	O
the	O
license	O
fee	O
represented	O
a	O
significant	O
cost	O
.	O
</s>
<s>
Nevertheless	O
,	O
this	O
was	O
going	O
to	O
occur	O
at	O
some	O
point	O
,	O
and	O
more	O
annoying	O
,	O
could	O
happen	O
at	O
random	O
in	O
a	O
binary	O
file	O
,	O
like	O
a	O
.zip	B-General_Concept
.	O
</s>
<s>
Hayes	O
estimated	O
that	O
a	O
user	O
transmitting	O
files	O
for	O
one	O
hour	O
a	O
day	O
would	O
encounter	O
about	O
six	O
files	O
per	O
year	O
that	O
randomly	O
contained	O
this	O
sequence	O
and	O
drop	O
the	O
modem	B-Application
into	O
command	O
mode	O
.	O
</s>
<s>
"	O
,	O
claiming	O
that	O
the	O
TIES	O
system	O
would	O
make	O
modems	B-Application
unreliable	O
.	O
</s>
<s>
Sierra	O
Semiconductor	O
,	O
which	O
manufactured	O
modem	B-Application
chipsets	O
that	O
supported	O
TIES	O
,	O
had	O
already	O
won	O
two	O
preliminary	O
injunctions	O
in	O
Minnesota	O
and	O
California	O
.	O
</s>
<s>
Some	O
even	O
offered	O
versions	O
with	O
both	O
TIES	O
and	O
Hayes	O
escape	O
sequences	O
,	O
which	O
could	O
be	O
determined	O
via	O
AT	O
commands	O
that	O
returned	O
the	O
internal	O
configuration	O
of	O
the	O
modem	B-Application
,	O
typically	O
ATI4	O
.	O
</s>
<s>
TIES	O
was	O
seen	O
mostly	O
in	O
"	O
off-brand	O
"	O
1200	O
and	O
2400	O
bit/s	O
modems	B-Application
,	O
which	O
were	O
never	O
a	O
large	O
market	O
compared	O
to	O
the	O
high-speed	O
models	O
that	O
followed	O
,	O
it	O
quickly	O
disappeared	O
in	O
the	O
early	O
1990s	O
when	O
almost	O
all	O
manufacturers	O
switched	O
to	O
Rockwell	O
chipsets	O
,	O
or	O
one	O
of	O
its	O
many	O
clones	O
.	O
</s>
<s>
Apparently	O
,	O
for	O
some	O
time	O
a	O
number	O
of	O
Hayes	O
employees	O
would	O
post	O
to	O
the	O
Usenet	B-Application
with	O
strings	O
like	O
"	O
+++ATH	O
"	O
in	O
the	O
text	O
.	O
</s>
<s>
This	O
would	O
cause	O
a	O
TIES	O
modem	B-Application
to	O
hang	O
up	O
.	O
</s>
<s>
It	O
was	O
also	O
used	O
on	O
IRC	B-Protocol
to	O
disconnect	O
people	O
using	O
dial-up	O
Internet	O
access	O
by	O
sending	O
ICMP	B-Protocol
ECHO	O
REQUEST	O
containing	O
the	O
string	O
+++ATH0	O
and	O
thus	O
the	O
modem	B-Application
hanging	O
up	O
when	O
the	O
victims	O
 '	O
computer	O
sent	O
back	O
the	O
ICMP	B-Protocol
payload	O
in	O
the	O
reply	O
.	O
</s>
<s>
TIES	O
however	O
is	O
still	O
used	O
today	O
in	O
many	O
modems	B-Application
especially	O
ones	O
by	O
Conexant	O
.	O
</s>
